643 
MR. H. B. DIXON ON CONDITIONS OF CHEMICAL CHANGE 
In this series a slight difference is produced by a change in the length of column. 
The difference is in the same direction, but not so well marked as in the previous 
experiments, in which the mixture was poorer in oxygen and was fired under 
50 millims. less pressure. It seemed likely that with higher initial pressures or 
with more oxygen the difference would disappear altogether. 
To x test this point another mixture was made still richer in electrolytic gas, and 
was exploded alternately near lines 200 and 800 in the eudiometer, under 250 millims. 
pressure and between 6 °'7 and 9° C. 
Composition of Mixture. 
Carbonic oxide. 41 "02 
Hydrogen. 39‘28 
Oxygen .. 19’70 
lUO'OO 
Table X.— At 250 millims. pressure. 
Reference 
No. 
Length of column. 
TJ l ■ CO., 
Eal,0 iDj 
1 
Temperature. 
millims. 
°c. 
16 
200 
■39 
9-0 
17 
200 
'385 
7*4 
18 
800 
•385 
7-9 
19 
800 
•39 
67 
These experiments show that with mixtures containing 20 per cent, of oxygen under 
250 millims. pressure, the division of the oxygen is independent of changes in the 
length of the column of gases. But with a lower initial pressure, this mixture is 
susceptible to an alteration in the length of column, as is shown by the following ex¬ 
periments :—A portion of the mixture was exploded under 100 millims. pressure, at 
the line 300 ; and a second portion was exploded under 100 millims. pressure, at the 
line 800. 
Table XI.—At 100 millims. pressure. 
Reference 
No. 
Leng'h of column. 
Ratio Hk 
H.,0 
Temperature. 
millims. 
° C. 
20 
300 
•42 
8-6 
21 
800 
•45 
9-8 
It appears from these series of experiments that for a given mixture of carbonic 
oxide and electrolytic gas, a change in the length of column causes an alteration in the 
division of the oxygen between the combustible gases so long as the pressure is kept 
